Tubotympanic disease: This is also known as
safe disease because it is bereft of any serious complications. The
infection is limited to the mucosa and the antero inferior part of
the middle ear cleft, hence the name. This disease does not have any
risk of bone erosion. The discharge any will flow through a
perforation present in the pars tensa portion of the ear drum. This
perforation is usually surrounded by a rim of remnant ear drum or
atleast the annulus is intact. (Central perforation).
The perforation is usually reniform (kidney shaped) because
of poor blood supply to the affected portion of the tympanic
membrane.

The infective activity of safe disease is
related to the frequency of upper respiratory tract infections, the
discharge tending to increase with increasing freqency of upper
respiratory infections.

Aetiology:

1. Could be a sequelae to inadequately treated
acute otitis media.

2. Acute suppurative otitis media causing
persistant perforation which could be infected from bacteria in the
external auditory canal. This condition is knonw as persistant
perforation syndrome.

Microbiology of CSOM: In all
varieties of CSOM the major organism found in the discharge are gram
negative bacilli i.e. Ps. aeruginosa, E. coli, and B. proteus. These
organisms are not commonly found in the upper respiratory tract, but
they are found in the skin of external auditory canal.

Clinical features of tubotympanic disease:

1. The discharge in this condition is profuse
and mucopurulent in nature.

2. The discharge is not foul
smelling.

3. Since the infected area is open at both
ends i.e. the eustachean tube end and the perforation in the ear
drum, the discharge doesnot accumulate in the middle
ear.

4. The ossicular chain is not at risk in this
type of disorder, the conductive deafness caused is
due to the presence of perforation in the tympanic membrane and
thickening of the tympanic membrane.

5. Conductive deafness may also be accentuated
by thickening of round window membrane due to the presence of
secretions. Hearing loss is usually about 30 - 40
dB.

6. These patients have poorly pneumatised /
sclerosed mastoid air cell system. This feature has been attributed
to repeated attacks of middle ear infections during childhood
causing inadequate pneumatisation of mastoid air cell system. In
patients with pneumatised mastoid air cell system repeated middle
ear infections can cause sclerosis with evidence of new bone
formation. Mastoids in these patients may be sclerotic.

7. Pain in the ear when present is always
associated with otitis externa. This commonly occurs when the
patient attempts to clean the ear off the purulent secretions with a
ear bud or cotton tipped applicator.

Pathology of tubotympanic
disease:

Pathological changes depend on the stage of
the disease. The stages are as follows:

Acute stage: This is where the ear is actively
discharging. The mucosa of the middle ear cavity is hypertrophied,
and congested.

Inactive stage: This condition is
characterised by dry perfortion of ear drum, commonly in its antero
inferior part, close to the eustachean tube orifice. The middle ear
mucosa is normal.

Quiescent stage: Perforation of ear drum is
present, the middle ear is dry and mucosa may be normal or
hypertrophied.

Healed stage: Here the perforation of ear drum
has healed by formation of thin scar. There may even be
tympanosclerotic patches / chalky deposits on the ear drum. The
ossicular chain is invariably intact.

Suction method can be used to suck out
secretions from the external canal and the middle ear cavity. The
only disadvantage of this procedure is the risk of noise induced
deafness.

Syringing the affected ear with warm saline
mixed with acetic acid (1.5%) can be used to syringe the affected
ear. This solution not only clears the ear of its purulent
secretions, it also helps to remove crusts if present. The presence
of weak acetic acid has bacteriostatic effect.

Role of antibiotics in the management of
tubotympanic disease:

Antibiotics can be administered depending on
the culture report. The best route of administration is topical
because the presence of a large central perforation enables adequate
concentration of antibiotics to reach the middle ear mucosa.
Ototoxic drugs are to be avoided because the increased vascularity
present in the middle ear mucosa will cause easy absorption of the
drug into the inner ear fluids causing sensori neural hearing loss.
Ciprofloxacillin can be administered topically.

Oral amoxycillin in adequate doses or
penicillins in adequate doses may be beneficial.

Role of antihistamines and nasal
decongestants: Is questionable. Their role is to
decongest the nasal and naso pharyngeal mucosa, pharyngeal end of
eustachean tube. Since there is associated perforation of tympanic
membrane, secretions dont tend to accumulate inside the middle ear
cavity. Topical nasal decongestants should not be used for more than
a week, because of their propensity to cause rhinitis
medicamentosa.

Precautions:

1. The ear must be kept dry.
This can be achieved by keeping the ears plugged
when taking head bath. Swimming must be avoided till the perforation
heals.

2. Pre existing sinus infections if any must
be treated aggressively.

3. Presence of focal sepsis in the throat
(tonsils commonly) must be ruled out.

The presence of deviated nasal septum must be
corrected as this could predispose to chronic sinus
infections.

If focal sepsis is identified in the tonsils
and adenoid then adenotonsillectomy needs to be
performed.

After eradicating the possible focal sepsis
only attempt must be made to definitively treat the perforation. If
the ear drum has managed to stay dry for more than 6 months
myringoplasty can be performed. Temporalis fascia is used as
grafting material because of its availability in close proximity,
its thickness is more or less similar to that of normal ear drum.
One other added advantage is its low basal metabolic
rate.

If middle ear mucosa is wet and oedmatous then
cortical mastoidectomy should be resorted to if conservative
management fails. Mastoidectomy can always be combined with
myringoplasty in the same sitting.

Atticoantral type of disease (Unsafe type of
disease):

This is termed as unsafe because dangerous
intra cranial and extra cranial complications can occur, proving
fatal to the patient. This disease spreads by erosion of the bony
wall of the attic. Cholesteatoma is commonly present in this
condition. This disease is commonly seen in sclerosed mastoid
cavities. Presence of granulation tissue is also common in this
disorder.

This condition mainly affects the attic region
of the middle ear. This region is pretty crowded, with the presence
of the head of the malleus and incus. Any disease process involving
crowded portions tend to cause more complications. Bone erosion
occurs due to the presence of osteitic reaction in the bone tissue.

Definition of cholesteatoma: Cholesteatoma is
defined as a cystic bag like structure lined by stratified squamous
epithelium on a fibrous matrix. This sac contains desquamated
squamous epithelium. This sac is present in the attic region.
Cholesteatoma is also defined as 'skin in wrong
place'. Cholesteatoma is known to contain all the layers of skin
epithelium. The basal layer (germinating layer) is present on the
outer surface of cholesteatoma sac in contact with the walls of the
middle ear cleft.

Theories of bone invasion by
cholesteatoma:

1. Pressure theory - states that increase in
the pressure caused by enlarging cholesteatoma cause bone erosion.
Ischemia has been attributed as the cause in this
theory.

2. Enzymatic theory: Inside the cholesteatoma
are present multinucleated osteoclasts and histiocytes. These cells
release acid phosphatase, collagenase and other proteolytic enzymes.
These enzymes are known to cause bone erosion.

Congenital
cholesteatoma: is known to arise from embryonic cell rests
present in the middle ear cavity and temporal bone. These cell rests
are known to commonly occur in cerebello pontine angle and petrous
apex. Infact congenital cholesteatoma is seen as a whitish mass
behind an intact tympanic membrane.

Derlacki and Clemis laid down
the following as criteria to diagnose congenital
cholesteatoma:

1. The patient should not have previous
episodes of middle ear disease

2. Ear drum must be intact and
normal

3. It is purely an incidental
finding

4. If discharge and ear drum perforation is
present then it should be contrued that congential cholesteatoma has
managed to erode the tympanic membrane.

Clinical features: The disorder is an
incidental finding. The common location of congenital cholesteatoma
is the antero superior quadrant of tympanic membrane, postero
superior quadrant being the next common site of involvement.
Anteriorly situated congenital cholesteatomas are known to affect
the eustachean tube function causing conductive deafness due to
middle ear effusion, where as posterior congenital cholesteatoma is
known to cause conductive deafness due to impairment of ossicular
chain mobility.

Staging of congenital
cholesteatoma:

Staging as suggested by Derlacki and Clemis:
They were the first to stage congenital cholesteatoma. They
classified congenital cholesteatoma into

1. Petrous pyramid cholesteatoma

2. Cholesteatoma involving the mastoid
cavity

3. Cholesteatoma involving the middle ear
cavity.

Potsicsuggested
the following staging mechanism:

Stage I : Single quadrant involvement with no
ossicular / mastoid involvement.

Type I : Involvement of mesotympanum without
involvement of incus / stapes

Type II : Involvement of mesotympanum / attic
along with erosion of ossicles without extension into the mastoid
cavity

Type III : Involvement of mesotympanum with
mastoid extension

Staging this disease will help in deciding the
modality of treatment and in predicting the long term prognosis.

Acquired
Cholesteatoma: can be divided into two types, primary
acquired and secondary acquired cholesteatomas.

Primay acquired cholesteatoma: In this
condition there is no history of preexisting or previous episodes of
otitis media or perforation. Lesions just arise from the attic
region of the middle ear.

Secondary acquired cholesteatoma: always
follows active middle ear infection which manages to destroy the ear
drum along with the annulus. This type of destruction is common in
acute necrotising otitis media following exanthematous fevers like
measles etc.

Oto
endoscopic picture showing attic cholesteatoma

Theories to explain pathogenesis of
cholesteatoma:

Various theories have been postulated to
explain the pathogenesis of cholesteatoma. They are:

1. Cawthrone theory: This theory suggested by
cawthrone in 1963 suggested that cholesteatoma always originated
from congential embryonic cell rests present in various areas of the
temporal bone.

2. Theory of immigration: This theory was
suggested by Tumarkin. He was of the view that cholesteatoma was
derived by immigration of squamous epithelium from the deep portion
of the external auditory canal into the middle ear cleft through a
marginal perforation or a total perforation of the ear drum as seen
in acute necrotising otitis media.

3. Theory of invagination: This theory was
suggested by Toss. He theorised that persistent negative pressure in
the attic region causes invagination of pars flaccida causing a
retraction pocket. This retraction pocket becomes later filled with
desquamted epithelial debris which forms a nidus for the infection
to occur later. Common organisms known to infect this keratin debris
are Psuedomonas, E. coli, B. Proteus etc.

Toss also classified attic retraction pockets
into 4 grades:

1. Grade I: The retracted pars flaccida is not
in contact with the neck of the malleus.

2. Grade II: The retracted pars flaccida is in
contact with the neck of the malleus to such an extent that it seems
to clothe the neck of the malleus.

3. Grade III: Here inaddition to the retracted
pars flaccida being in contact with the neck of the malleus there is
also a limited erosion of the outer attic wall or
scutum.

4. Grade IV: In this grade in addition to all
the above said changes there is severe erosion of the outer attic
wall or scutum.

4.
Metaplastic theory: This theory was first suggested by Wendt in
1873. He took into consideration the histological changes seen in
various portions of the middle ear cavity. The attic area of the
middle ear cavity is lined by pavement type of epithelium. This
epithelium undergoes metaplastic changes in response to subclinical
infection. This metaplastic mucosa is squamous in nature there by
forming a nidus for cholesteatoma formation in the attic
region.

Of all the above mentioned theories, the
theory of invagination appears to be the most plausible one
currently explaining the various pathologic features of
cholesteatoma.

Clinical features of acquired
cholesteatoma:

Ear discharge: is scanty and foul smelling.
Infact the odur is best described as musty in nature. This is due to
the presence of saprophytic infection and osteitis.

Hearing loss: is commonly conductive in
nature. Some patients may even surprisingly have a normal hearing
despite the presence of a huge cholesteatoma. This normal hearing
could be attributed to the bridging effects of cholesteatomatous
mass.

Sensorineural hearing loss if present could be
attributed to the absorption of toxins through the round window
membrane, or may be due to use of ototoxic antibiotics topically on
a long term basis.

Ear ache: if present could be attributed to
the presence of co existing otitis externa, or presence of
extradural abscess.

Tinnitus if present may indicate imminent
sensorineural hearing loss.

Vertigo may be present if there is erosion of
lateral semicircular canal by the cholesteatomatous matrix.Fistula test if performed is positive in these
patient.

Fistula test: This test is positive if there
is a third window is present in the laryrinth due to the erosion of
the labyrinthine bone. This commonly occurs in the lateral
semicircular canal area. This test is performed using a snugly
fitting siegles pneumatic speculum and slowly applying pressure by
compressing the pneumatic bulb. If labyrinthine fistula is present
the patient will feel giddy and will have nystagmus.